Antenna selection devices, methods, &amp; systems

ABSTRACT

A method, an apparatus, and a computer program product for wireless communication are provided in connection with improving antenna selection for a UE as part of an access procedure. In an example, a UE with two or more antennas is equipped to obtain receive chain measurements for the two or more antennas associated with the UE when an access procedure is initiated, select an antenna, of the two or more antennas, for transmission based on receive chain measurements for use during at least a portion of the access procedure, and perform the access procedure using the selected antenna. In another example, the UE is equipped to determine that an Access procedure is to be initiated, select an antenna from the two or more antennas based on a selection algorithm, and perform the Access procedure based using the selected antenna. Other aspects, embodiments, and features are also claimed and described.

PRIORITY CLAIM & REFERENCE TO RELATED FILINGS

The present Application for Patent claims priority to and the benefit ofU.S. Provisional Application Nos. (a) 61/649,704, filed 21 May 2012; (b)61/716,582, filed 21 Oct. 2012; (c) 61/734,276, filed 6 Dec. 2012; (d)61/737,715, filed 14 Dec. 2012; (e) 61/716,586, filed 21 Oct. 2012; (f)61/716,599, filed 21 Oct. 2012; (g) 61/716,902, filed 22 Oct. 2012; and(h) 61/736,541, filed 12 Dec. 2012. All of said applications areassigned to the assignee hereof and are hereby expressly incorporated byreference herein as if fully set forth fully below in their entiretiesfor all applicable purposes.

TECHNICAL FIELD

The present disclosure relates generally to communication systems, andmore particularly, to improving antenna selection for a user equipment(UE) during an access procedure.

BACKGROUND

Wireless communication networks are widely deployed to provide variouscommunication services such as telephony, video, data, messaging,broadcasts, and so on. Such networks, which are usually multiple accessnetworks, support communications for multiple users by sharing theavailable network resources. One example of such a network is theUniversal Mobile Telecommunications System (UMTS) Terrestrial RadioAccess Network (UTRAN). The UTRAN is the radio access network (RAN)defined as a part of the UMTS, a third generation (3G) mobile phonetechnology supported by the 3rd Generation Partnership Project (3GPP).The UMTS, which is the successor to Global System for MobileCommunications (GSM) technologies, currently supports various airinterface standards, such as Wideband-Code Division Multiple Access(W-CDMA), Time Division—Code Division Multiple Access (TD-CDMA), andTime Division—Synchronous Code Division Multiple Access (TD-SCDMA). TheUMTS also supports enhanced 3G data communications protocols, such asHigh Speed Packet Access (HSPA), which provides higher data transferspeeds and capacity to associated UMTS networks.

As the demand for mobile broadband access continues to increase,research and development continue to advance the UMTS technologies notonly to meet the growing demand for mobile broadband access, but toadvance and enhance the user experience with mobile communications.

Generally, when a user attempts to originate a call or receives call,one antenna of two or more antennas of the UE may have some blockage(e.g., due to hand restriction, etc.), based on a device specificarchitecture. When such a blockage occurs, it is possible that a secondantenna of the UE has comparatively low blockage and hence routing anaccess procedure (e.g., access channel preambles/messages, etc.) throughthe second antenna may provide a comparatively better/faster chance toreach a network entity (e.g., NodeB, eNodeB, etc.).

BRIEF SUMMARY OF SOME SAMPLE EMBODIMENTS

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

In accordance with one or more aspects and corresponding disclosurethereof, various aspects are described in connection with improvingantenna selection for a UE as part of an access procedure. In anexample, a UE with two or more antennas is equipped to obtain receivechain measurements for the two or more antennas associated with the UEwhen an access procedure is initiated, select an antenna, of the two ormore antennas, for transmission based on receive chain measurements foruse during at least a portion of the access procedure, and perform theaccess procedure using the selected antenna. In another example, the UEis equipped to determine that an Access procedure is to be initiated,select an antenna from the two or more antennas based on a selectionalgorithm, and perform the Access procedure based using the selectedantenna.

According to related aspects, a method for improving antenna selectionfor a UE as part of an access procedure is provided. The method caninclude obtaining, by a UE, receive chain measurements for two or moreantennas associated with the UE when an access procedure is initiated.Further, the method can include selecting an antenna, of the two or moreantennas, for transmission based on receive chain measurements for useduring at least a portion of the access procedure. Moreover, the methodmay include performing the access procedure using the selected antenna.

Another aspect relates to a communications apparatus with improvedantenna selection as part of an access procedure. The communicationsapparatus can include means for obtaining, by a UE, receive chainmeasurements for two or more antennas associated with the UE when anaccess procedure is initiated. Further, the communications apparatus caninclude means for selecting an antenna, of the two or more antennas, fortransmission based on receive chain measurements for use during at leasta portion of the access procedure. Moreover, the communicationsapparatus can include means for performing the access procedure usingthe selected antenna.

Another aspect relates to a communications apparatus. The apparatus caninclude a processing system configured to obtain, by a UE, receive chainmeasurements for two or more antennas associated with the UE when anaccess procedure is initiated. Further, the processing system may beconfigured to select an antenna, of the two or more antennas, fortransmission based on receive chain measurements for use during at leasta portion of the access procedure. Moreover, the processing system mayfurther be configured to perform the access procedure using the selectedantenna.

Still another aspect relates to a computer program product, which canhave a computer-readable medium including code for obtaining, by a UE,receive chain measurements for two or more antennas associated with theUE when an access procedure is initiated. Further, the computer-readablemedium can include code for selecting an antenna, of the two or moreantennas, for transmission based on receive chain measurements for useduring at least a portion of the access procedure. Moreover, thecomputer-readable medium can include code for performing the accessprocedure using the selected antenna.

According to related aspects, a method for improving antenna selectionfor a UE as part of an access procedure is provided. The method caninclude determining that an Access procedure is to be initiated.Further, the method can include selecting an antenna, from the two ormore antennas, for transmission based on a selection algorithm.Moreover, the method may include performing the Access procedure basedusing the selected antenna.

Another aspect relates to a communications apparatus with improvedantenna selection as part of an access procedure. The communicationsapparatus can include means for determining that an Access procedure isto be initiated. Further, the communications apparatus can include meansfor selecting an antenna, from the two or more antennas, fortransmission based on a selection algorithm. Moreover, thecommunications apparatus can include means for performing the Accessprocedure based using the selected antenna.

Another aspect relates to a communications apparatus. The apparatus caninclude a processing system configured to determine that an Accessprocedure is to be initiated. Further, the processing system may beconfigured to select an antenna, from the two or more antennas, fortransmission based on a selection algorithm. Moreover, the processingsystem may further be configured to perform the Access procedure basedusing the selected antenna.

Still another aspect relates to a computer program product, which canhave a computer-readable medium including code for determining that anAccess procedure is to be initiated. Further, the computer-readablemedium can include code for selecting an antenna, from the two or moreantennas, for transmission based on a selection algorithm. Moreover, thecomputer-readable medium can include code for performing the Accessprocedure based using the selected antenna.

Other aspects, features, and embodiments of the present invention willbecome apparent to those of ordinary skill in the art, upon reviewingthe following description of specific, exemplary embodiments of thepresent invention in conjunction with the accompanying figures. Whilefeatures of the present invention may be discussed relative to certainembodiments and figures below, all embodiments of the present inventioncan include one or more of the advantageous features discussed herein.In other words, while one or more embodiments may be discussed as havingcertain advantageous features, one or more of such features may also beused in accordance with the various embodiments of the inventiondiscussed herein. In similar fashion, while exemplary embodiments may bediscussed below as device, system, or method embodiments it should beunderstood that such exemplary embodiments can be implemented in variousdevices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of an access networkarchitecture according to some embodiments.

FIG. 2 is a diagram illustrating an example of another access networkarchitecture according to some embodiments.

FIG. 3 is a diagram illustrating an example of a network entity and userequipment in an access network according to some embodiments.

FIG. 4 is a diagram illustrating an example of another access networkarchitecture, according to some embodiments.

FIG. 5 is a diagram illustrating an example of an UL frame structure inLTE according to some embodiments.

FIG. 6 is a diagram illustrating events for a mobile terminated callover time according to some embodiments.

FIG. 7 is a flow chart illustrating a first example method for improvingwireless device power consumption in an M2M environment according tosome embodiments.

FIG. 8 is a flow chart illustrating a second example method forimproving wireless device power consumption in an M2M environmentaccording to some embodiments.

FIG. 9 is a conceptual data flow diagram illustrating the data flowbetween different modules/means/components according to someembodiments.

FIG. 10 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system accordingto some embodiments.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, modules, components,circuits, steps, processes, algorithms, etc. (collectively referred toas “elements”). These elements may be implemented using electronichardware, computer software, or any combination thereof Whether suchelements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented with a “processing system”that includes one or more processors. Examples of processors includemicroprocessors, microcontrollers, digital signal processors (DSPs),field programmable gate arrays (FPGAs), programmable logic devices(PLDs), state machines, gated logic, discrete hardware circuits, andother suitable hardware configured to perform the various functionalitydescribed throughout this disclosure. One or more processors in theprocessing system may execute software. Software shall be construedbroadly to mean instructions, instruction sets, code, code segments,program code, programs, subprograms, software modules, applications,software applications, software packages, routines, subroutines,objects, executables, threads of execution, procedures, functions, etc.,whether referred to as software, firmware, middleware, microcode,hardware description language, or otherwise.

Accordingly, in one or more exemplary embodiments, the functionsdescribed may be implemented in hardware, software, firmware, or anycombination thereof If implemented in software, the functions may bestored on or encoded as one or more instructions or code on acomputer-readable medium. Computer-readable media includes computerstorage media. Storage media may be any available media that can beaccessed by a computer. By way of example, and not limitation, suchcomputer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code in the form of instructions or data structures and that canbe accessed by a computer. Disk and disc, as used herein, includescompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), and floppy disk where disks usually reproduce data magnetically,while discs reproduce data optically with lasers. Combinations of theabove should also be included within the scope of computer-readablemedia.

By way of example and without limitation, the aspects of the presentdisclosure illustrated in FIG. 1 are presented with reference to a UMTSsystem 100 employing a W-CDMA air interface and/or CDMA2000 airinterface. A UMTS network includes three interacting domains: a CoreNetwork (CN) 104, a UMTS Terrestrial Radio Access Network (UTRAN) 102,and User Equipment (UE) 110. In this example, the UTRAN 102 providesvarious wireless services including telephony, video, data, messaging,broadcasts, and/or other services. The UTRAN 102 may include a pluralityof Radio Network Subsystems (RNSs) such as an RNS 107, each controlledby a respective Radio Network Controller (RNC) such as an RNC 106. Here,the UTRAN 102 may include any number of RNCs 106 and RNSs 107 inaddition to the RNCs 106 and RNSs 107 illustrated herein. The RNC 106 isan apparatus responsible for, among other things, assigning,reconfiguring, and releasing radio resources within the RNS 107. The RNC106 may be interconnected to other RNCs (not shown) in the UTRAN 102through various types of interfaces such as a direct physicalconnection, a virtual network, or the like, using any suitable transportnetwork.

Communication between a UE 110 and a Node B 108 may be considered asincluding a physical (PHY) layer and a medium access control (MAC)layer. Further, communication between a UE 110 and an RNC 106 by way ofa respective Node B 108 may be considered as including a radio resourcecontrol (RRC) layer. In the instant specification, the PHY layer may beconsidered layer 1; the MAC layer may be considered layer 2; and the RRClayer may be considered layer 3. Information hereinbelow utilizesterminology introduced in the RRC Protocol Specification, 3GPP TS 25.331v9.1.0, incorporated herein by reference.

The geographic region covered by the RNS 107 may be divided into anumber of cells, with a radio transceiver apparatus serving each cell. Aradio transceiver apparatus is commonly referred to as a Node B in UMTSapplications, but may also be referred to by those skilled in the art asa base station (BS), a base transceiver station (BTS), a radio basestation, a radio transceiver, a transceiver function, a basic serviceset (BSS), an extended service set (ESS), an access point (AP), or someother suitable terminology. For clarity, three Node Bs 108 are shown ineach RNS 107; however, the RNSs 107 may include any number of wirelessNode Bs. The Node Bs 108 provide wireless access points to a CN 104 forany number of mobile apparatuses. Examples of a mobile apparatus includea cellular phone, a smart phone, a session initiation protocol (SIP)phone, a laptop, a notebook, a netbook, a smartbook, a personal digitalassistant (PDA), a satellite radio, a global positioning system (GPS)device, a multimedia device, a video device, a digital audio player(e.g., MP3 player), a camera, a game console, or any other similarfunctioning device. The mobile apparatus is commonly referred to as a UEin UMTS applications, but may also be referred to by those skilled inthe art as a mobile station, a subscriber station, a mobile unit, asubscriber unit, a wireless unit, a remote unit, a mobile device, awireless device, a wireless communications device, a remote device, amobile subscriber station, an access terminal, a mobile terminal, awireless terminal, a remote terminal, a handset, a terminal, a useragent, a mobile client, a client, or some other suitable terminology.For illustrative purposes, one UE 110 is shown in communication with anumber of the Node Bs 108. The DL, also called the forward link, refersto the communication link from a Node B 108 to a UE 110, and the UL,also called the reverse link, refers to the communication link from a UE110 to a Node B 108.

Further, UE 110 may be equipped with multiple antennas 111 that mayenable communication using one or more radio access technologies (RATs).The multiple antennas 111 may be used for transmit diversity, rangeextension, etc. In an aspect, UE 110 may select an antenna from themultiple antennas 111 to use to access the network (e.g., Node B 108).In such an aspect, the UE 110 selection may be based on downlinkmeasurements from the antennas 111. In an operational aspect, a user mayattempt to originate a call (mobile originated (MO)) and/or receive call(mobile terminated (MT)). Further, one antenna the multiple antennas 111may experience some blockage (e.g., due to hand restriction, etc.). Insuch an aspect, a second antenna of the UE 110 may experience relativelylow blockage and hence routing the preambles/messages through the secondantenna may result in an improved (e.g., more reliable and faster)chance to communicate with Node B 108.

The CN 104 interfaces with one or more access networks, such as theUTRAN 102. As shown, the CN 104 is a GSM core network. However, as thoseskilled in the art will recognize, the various concepts presentedthroughout this disclosure may be implemented in a RAN, or othersuitable access network, to provide UEs with access to types of CNsother than GSM networks.

The CN 104 includes a circuit-switched (CS) domain and a packet-switched(PS) domain. Some of the circuit-switched elements are a Mobile servicesSwitching Centre (MSC) 112, a Visitor location register (VLR), and aGateway MSC. Packet-switched elements include a Serving GPRS SupportNode (SGSN) and a Gateway GPRS Support Node (GGSN). Some networkelements, like EIR, HLR, VLR and AuC may be shared by both of thecircuit-switched and packet-switched domains. In the illustratedexample, the CN 104 supports circuit-switched services with a MSC 112and a GMSC 114. In some applications, the GMSC 114 may be referred to asa media gateway (MGW). One or more RNCs, such as the RNC 106, may beconnected to the MSC 112. The MSC 112 is an apparatus that controls callsetup, call routing, and UE mobility functions. The MSC 112 may alsoinclude a VLR that contains subscriber-related information for theduration that a UE is in the coverage area of the MSC 112. The GMSC 114provides a gateway through the MSC 112 for the UE to access acircuit-switched network 116. The GMSC 114 includes a home locationregister (HLR) 115 containing subscriber data, such as the datareflecting the details of the services to which a particular user hassubscribed. The HLR is also associated with an authentication center(AuC) that contains subscriber-specific authentication data. When a callis received for a particular UE, the GMSC 114 queries the HLR 115 todetermine the UE's location and forwards the call to the particular MSCserving that location.

The CN 104 also supports packet-data services with a serving GeneralPacket Radio Service (GPRS) support node (SGSN) 118 and a gateway GPRSsupport node (GGSN) 120. GPRS is designed to provide packet-dataservices at speeds higher than those available with standardcircuit-switched data services. The GGSN 120 provides a connection forthe UTRAN 102 to a packet-based network 122. The packet-based network122 may be the Internet, a private data network, or some other suitablepacket-based network. The primary function of the GGSN 120 is to providethe UEs 110 with packet-based network connectivity. Data packets may betransferred between the GGSN 120 and the UEs 110 through the SGSN 118,which performs primarily the same functions in the packet-based domainas the MSC 112 performs in the circuit-switched domain.

An air interface for UMTS may utilize a spread spectrum Direct-SequenceCode Division Multiple Access (DS-CDMA) system. The spread spectrumDS-CDMA spreads user data through multiplication by a sequence ofpseudorandom bits called chips. The “wideband” W-CDMA air interface forUMTS is based on such direct sequence spread spectrum technology andadditionally calls for a frequency division duplexing (FDD). FDD uses adifferent carrier frequency for the UL and DL between a Node B 108 and aUE 110. Another air interface for UMTS that utilizes DS-CDMA, and usestime division duplexing (TDD), is the TD-SCDMA air interface. Thoseskilled in the art will recognize that although various examplesdescribed herein may refer to a W-CDMA air interface, the underlyingprinciples may be equally applicable to a TD-SCDMA air interface.

FIG. 2 is a diagram illustrating an LTE network architecture 200. TheLTE network architecture 200 may be referred to as an Evolved PacketSystem (EPS) 200. The EPS 200 may include one or more user equipment(UE) 202, an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN)204, an Evolved Packet Core (EPC) 210, a Home Subscriber Server (HSS)220, and an Operator's IP Services 222. The EPS can interconnect withother access networks, but for simplicity those entities/interfaces arenot shown. As shown, the EPS provides packet-switched services, however,as those skilled in the art will readily appreciate, the variousconcepts presented throughout this disclosure may be extended tonetworks providing circuit-switched services.

The E-UTRAN includes the evolved Node B (eNB) 206 and other eNBs 208.The eNB 206 provides user and control planes protocol terminationstoward the UE 202. The eNB 206 may be connected to the other eNBs 208via a backhaul (e.g., an X2 interface). The eNB 206 may also be referredto as a base station, a base transceiver station, a radio base station,a radio transceiver, a transceiver function, a basic service set (BSS),an extended service set (ESS), or some other suitable terminology. TheeNB 206 provides an access point to the EPC 210 for a UE 202. Examplesof UEs 202 include a cellular phone, a smart phone, a session initiationprotocol (SIP) phone, a laptop, a personal digital assistant (PDA), asatellite radio, a global positioning system, a multimedia device, avideo device, a digital audio player (e.g., MP3 player), a camera, agame console, or any other similar functioning device. The UE 202 mayalso be referred to by those skilled in the art as a mobile station, asubscriber station, a mobile unit, a subscriber unit, a wireless unit, aremote unit, a mobile device, a wireless device, a wirelesscommunications device, a remote device, a mobile subscriber station, anaccess terminal, a mobile terminal, a wireless terminal, a remoteterminal, a handset, a user agent, a mobile client, a client, or someother suitable terminology.

The eNB 206 is connected by an 51 interface to the EPC 210. The EPC 210includes a Mobility Management Entity (MME) 212, other MMEs 214, aServing Gateway 216, and a Packet Data Network (PDN) Gateway 218. TheMME 212 is the control node that processes the signaling between the UE202 and the EPC 210. Generally, the MME 212 provides bearer andconnection management. All user IP packets are transferred through theServing Gateway 216, which itself is connected to the PDN Gateway 218.The PDN Gateway 218 provides UE IP address allocation as well as otherfunctions. The PDN Gateway 218 is connected to the Operator's IPServices 222. The Operator's IP Services 222 may include the Internet,the Intranet, an IP Multimedia Subsystem (IMS), and a PS StreamingService (PSS).

Further, UE 202 may be equipped with multiple antennas 203 that mayenable communication using one or more radio access technologies (RATs).The multiple antennas 203 may be used for transmit diversity, rangeextension, etc. In an aspect, UE 202 may select an antenna from themultiple antennas 203 to use to access the network (e.g., perform anaccess channel (ACH) procedure). In an aspect, the ACH procedure may bea random access channel (RACH) procedure. In such an aspect, the UE 202selection may be based on downlink measurements from the antennas 203.In an operational aspect, a user may attempt to originate a call (MO)and/or receive call (MT). Further, one antenna the multiple antennas 203may experience some blockage (e.g., due to hand restriction, etc.). Insuch an aspect, a second antenna of the UE 203 may experience relativelylow blockage and hence routing the preambles/messages through the secondantenna may result in an improved (e.g., more reliable and faster)chance to communicate with eNB 206.

The modulation and multiple access scheme employed by the access network200 may vary depending on the particular telecommunications standardbeing deployed. In LTE applications, OFDM is used on the DL and SC-FDMAis used on the UL to support both frequency division duplexing (FDD) andtime division duplexing (TDD). As those skilled in the art will readilyappreciate from the detailed description to follow, the various conceptspresented herein are well suited for LTE applications. However, theseconcepts may be readily extended to other telecommunication standardsemploying other modulation and multiple access techniques. By way ofexample, these concepts may be extended to Evolution-Data Optimized(EV-DO) or Ultra Mobile Broadband (UMB). EV-DO and UMB are air interfacestandards promulgated by the 3rd Generation Partnership Project 2(3GPP2) as part of the CDMA2000 family of standards and employs CDMA toprovide broadband Internet access to mobile stations. These concepts mayalso be extended to Universal Terrestrial Radio Access (UTRA) employingWideband-CDMA (W-CDMA) and other variants of CDMA, such as TD-SCDMA;Global System for Mobile Communications (GSM) employing TDMA; andEvolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, and Flash-OFDM employing OFDMA. UTRA, E-UTRA, UMTS, LTE and GSMare described in documents from the 3GPP organization. CDMA2000 and UMBare described in documents from the 3GPP2 organization. The actualwireless communication standard and the multiple access technologyemployed will depend on the specific application and the overall designconstraints imposed on the system.

Spatial multiplexing is generally used when channel conditions are good.When channel conditions are less favorable, beamforming may be used tofocus the transmission energy in one or more directions. This may beachieved by spatially precoding the data for transmission throughmultiple antennas. To achieve good coverage at the edges of the cell, asingle stream beamforming transmission may be used in combination withtransmit diversity.

In the detailed description that follows, various aspects of an accessnetwork will be described with reference to a MIMO system supportingOFDM on the DL. OFDM is a spread-spectrum technique that modulates dataover a number of subcarriers within an OFDM symbol. The subcarriers arespaced apart at precise frequencies. The spacing provides“orthogonality” that enables a receiver to recover the data from thesubcarriers. In the time domain, a guard interval (e.g., cyclic prefix)may be added to each OFDM symbol to combat inter-OFDM-symbolinterference. The UL may use SC-FDMA in the form of a DFT-spread OFDMsignal to compensate for high peak-to-average power ratio (PAPR).

FIG. 3 is a block diagram of a network entity 310 (e.g., NodeB, eNB,pico node, a femto node, etc.) in communication with a UE 350 in anaccess network. In the DL, upper layer packets from the core network areprovided to a controller/processor 375. The controller/processor 375implements the functionality of the L2 layer. In the DL, thecontroller/processor 375 provides header compression, ciphering, packetsegmentation and reordering, multiplexing between logical and transportchannels, and radio resource allocations to the UE 350 based on variouspriority metrics. The controller/processor 375 is also responsible forHARQ operations, retransmission of lost packets, and signaling to the UE350.

The transmit (TX) processor 316 implements various signal processingfunctions for the L1 layer (i.e., physical layer). The signal processingfunctions includes coding and interleaving to facilitate forward errorcorrection (FEC) at the UE 350 and mapping to signal constellationsbased on various modulation schemes (e.g., binary phase-shift keying(BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying(M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded andmodulated symbols are then split into parallel streams. Each stream isthen mapped to an OFDM subcarrier, multiplexed with a reference signal(e.g., pilot) in the time and/or frequency domain, and then combinedtogether using an Inverse Fast Fourier Transform (IFFT) to produce aphysical channel carrying a time domain OFDM symbol stream. The OFDMstream is spatially precoded to produce multiple spatial streams.Channel estimates from a channel estimator 374 may be used to determinethe coding and modulation scheme, as well as for spatial processing. Thechannel estimate may be derived from a reference signal and/or channelcondition feedback transmitted by the UE 350. Each spatial stream isthen provided to a different antenna 320 via a separate transmitter318TX. Each transmitter 318TX modulates an RF carrier with a respectivespatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through itsrespective antenna 352. Each receiver 354RX recovers informationmodulated onto an RF carrier and provides the information to the receive(RX) processor 356. The RX processor 356 implements various signalprocessing functions of the L1 layer. The RX processor 356 performsspatial processing on the information to recover any spatial streamsdestined for the UE 350. If multiple spatial streams are destined forthe UE 350, they may be combined by the RX processor 356 into a singleOFDM symbol stream. The RX processor 356 then converts the OFDM symbolstream from the time-domain to the frequency domain using a Fast FourierTransform (FFT). The frequency domain signal comprises a separate OFDMsymbol stream for each subcarrier of the OFDM signal. The symbols oneach subcarrier, and the reference signal, is recovered and demodulatedby determining the most likely signal constellation points transmittedby the network entity 310. These soft decisions may be based on channelestimates computed by the channel estimator 358. The soft decisions arethen decoded and deinterleaved to recover the data and control signalsthat were originally transmitted by the network entity 310 on thephysical channel. The data and control signals are then provided to thecontroller/processor 359.

The controller/processor 359 implements the L2 layer. Thecontroller/processor can be associated with a memory 360 that storesprogram codes and data. The memory 360 may be referred to as acomputer-readable medium. In the UL, the controller/processor 359provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover upper layer packets from the core network. The upper layerpackets are then provided to a data sink 362, which represents all theprotocol layers above the L2 layer. Various control signals may also beprovided to the data sink 362 for L3 processing. Thecontroller/processor 359 is also responsible for error detection usingan acknowledgement (ACK) and/or negative acknowledgement (NACK) protocolto support HARQ operations.

In the UL, a data source 367 is used to provide upper layer packets tothe controller/processor 359. The data source 367 represents allprotocol layers above the L2 layer. Similar to the functionalitydescribed in connection with the DL transmission by the network entity310, the controller/processor 359 implements the L2 layer for the userplane and the control plane by providing header compression, ciphering,packet segmentation and reordering, and multiplexing between logical andtransport channels based on radio resource allocations by the networkentity 310. The controller/processor 359 is also responsible for HARQoperations, retransmission of lost packets, and signaling to the networkentity 310.

Channel estimates derived by a channel estimator 358 from a referencesignal or feedback transmitted by the network entity 310 may be used bythe TX processor 368 to select the appropriate coding and modulationschemes, and to facilitate spatial processing. The spatial streamsgenerated by the TX processor 368 are provided to different antenna 352via separate transmitters 354TX. Each transmitter 354TX modulates an RFcarrier with a respective spatial stream for transmission.

The UL transmission is processed at the network entity 310 in a mannersimilar to that described in connection with the receiver function atthe UE 350. Each receiver 318RX receives a signal through its respectiveantenna 320. Each receiver 318RX recovers information modulated onto anRF carrier and provides the information to a RX processor 370. The RXprocessor 370 may implement the L1 layer.

The controller/processor 375 implements the L2 layer. Thecontroller/processor 375 can be associated with a memory 376 that storesprogram codes and data. The memory 376 may be referred to as acomputer-readable medium. In the UL, the controller/processor 375provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover upper layer packets from the UE 350. Upper layer packets fromthe controller/processor 375 may be provided to the core network. Thecontroller/processor 375 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations.

FIG. 4 depicts an example communication network 400 in which efficientantenna selection as part of an access procedure may be enabled,according to an aspect.

Communication network 400 may include a wireless device 402 (e.g., UE110, UE 202, etc.), and a network entity 430 (e.g., Node B, eNB, etc.).

Wireless device 402 may include an application processing subsystem 404,access procedure module 408, and modem subsystem 414. In an aspect,application processing subsystem 404 may use data transaction module 406to obtain data as part of a MO call initiation. In an aspect, modemsubsystem 414 may receive a page message (e.g., paging indicator) form anetwork entity 430 as part of a MT call initiation. In an aspect, accessprocedure module 408 may determine that an access procedure is to beinitiated based on internal reception of a message from the applicationprocessing subsystem 404 and/or the modem subsystem 414. Althoughdepicted as a separate module in FIG. 4, access procedure module 408 maybe associated with and/or coupled to application processing subsystem404 and/or modem subsystem 414. In another aspect, access proceduremodule 408 may include multiple sub-portions, and a sub-portion may bemore closely coupled to the modem subsystem 414. In another aspect,modem subsystem 414 may be coupled to multiple antennas 418, 420 andconfigured to use multiple radios 416. Although FIG. 4 depicts only twoantennas 418, 420, one or ordinary skill in the art understands that thewireless device is not limited to two antennas and may have additionalantennas beyond the depicted.

Access procedure module 408 may include a receive chain measurementsmodule 410 and transmit antenna selection module 412. In an aspect,receive chain measurements module 410 may receive antenna 418, 420receive chain measurements (422, 424) via modem subsystem 414. In anaspect, the UE measurements may include, but are not limited to areceive signal code power (RSCP) measurement, a Reference SignalReceived Power (RSRP) measurement, a Received Signal Strength Indication(RSSI) measurement, an automatic gain control (AGC) measurement, etc. Inan aspect, transmit antenna selection module 412 may select an antenna(e.g., 420) for transmissions 426 for at least a portion of an accessprocedure (e.g., access channel (ACH) procedure). Generally, an antenna420 that has greater Rx chain measurement value 424 may also have lesspath loss on a downlink. As such, transmit antenna selection module 412may select this antenna 420 for transmissions 426 as it may have agreater chance of having lower path loss on an uplink. Furtherdescription of an operational aspect, of access procedure module 408 isprovided with reference to the flowchart in FIG. 7 below. In anotheraspect, transmit antenna selection module 412 may use a selectionalgorithm to select which antenna to use for transmissions. In anaspect, the selection algorithm may prompt the wireless device 402 torandomly and/or pseudo-randomly select an antenna 418, 420 fortransmissions for at least a portion of the Access procedure. In anotheraspect, the selection algorithm may prompt the wireless device 402 toselect an antenna 418, 420 based on a pre-determined antenna hoppingpattern (e.g., antenna 0, then 1, then 0, then 1, etc.). In anotheraspect, the selection algorithm may prompt the wireless device 402 tousing an antenna that was most recently previously successfully used.Further description of an operational aspect, of access procedure module408 is provided with reference to the flowchart in FIG. 8 below.

FIG. 5 is a diagram 500 illustrating an example of an UL frame structurein LTE.

The available resource blocks for the UL may be partitioned into a datasection and a control section. The control section may be formed at thetwo edges of the system bandwidth and may have a configurable size. Theresource blocks in the control section may be assigned to UEs fortransmission of control information. The data section may include allresource blocks not included in the control section. The UL framestructure results in the data section including contiguous subcarriers,which may allow a single UE to be assigned all of the contiguoussubcarriers in the data section.

A UE may be assigned resource blocks 510 a, 510 b in the control sectionto transmit control information to an eNB. The UE may also be assignedresource blocks 520 a, 520 b in the data section to transmit data to theeNB. The UE may transmit control information in a physical UL controlchannel (PUCCH) on the assigned resource blocks in the control section.The UE may transmit only data or both data and control information in aphysical UL shared channel (PUSCH) on the assigned resource blocks inthe data section. A UL transmission may span both slots of a subframeand may hop across frequency.

A set of resource blocks may be used to perform initial system accessand achieve UL synchronization in a physical random access channel(PRACH) 530. The PRACH 530 carries a random sequence and may carry atransmit preamble on an access slot boundary (e.g., ˜1 ms (4096 chips)using 1 of 16 signatures). Each random access preamble occupies abandwidth corresponding to six consecutive resource blocks. The startingfrequency is specified by the network. That is, the transmission of therandom access preamble is restricted to certain time and frequencyresources. There is no frequency hopping for the PRACH. The PRACHattempt is carried in a single subframe (1 ms) or in a sequence of fewcontiguous subframes and a UE can make only a single PRACH attempt perframe (10 ms).

FIG. 6 illustrating events 600 over time 602 for a mobile terminatedcall in an LTE based access network, according to an aspect.

As noted with reference to FIGS. 2 and 5, UTRAN 204 may communicate withUE 202 using a paging channel. Paging 606 may occurs through settingPaging Indicator (PI) symbol ON in the PICH. When UE 202 wakes up 604 inits DRX cycle, it may monitor for the PI symbol. When the PI symbol isset to ON, the UE 202 may read paging messages of PCH Tr Ch in SCCPCHphysical channel 608 (which occurs Tau _(—) _(PICH) (3 slots, or 7680chips) later). Subsequently, a forward access channel (FACH) may beinitiated 610 and the UE 202 may select 612 an antenna to use for theaccess channel procedure. In an aspect, the antenna may be selectedbased on receive chain measurements. In another aspect, the antenna maybe selected based on a selection algorithm. Thereafter, UE 202 mayinitiate a RACH procedure 614 using PRACH 530 through the selectedantenna to get radio access to send L3 messaging (e.g., a RRC ConnectionRequest message) 616.

FIGS. 7 and 8 illustrate various methodologies in accordance withvarious aspects of the presented subject matter. While, for purposes ofsimplicity of explanation, the methodologies are shown and described asa series of acts or sequence steps, it is to be understood andappreciated that the claimed subject matter is not limited by the orderof acts, as some acts may occur in different orders and/or concurrentlywith other acts from that shown and described herein. For example, thoseskilled in the art will understand and appreciate that a methodologycould alternatively be represented as a series of interrelated states orevents, such as in a state diagram. Moreover, not all illustrated actsmay be required to implement a methodology in accordance with theclaimed subject matter. Additionally, it should be further appreciatedthat the methodologies disclosed hereinafter and throughout thisspecification are capable of being stored on an article of manufactureto facilitate transporting and transferring such methodologies tocomputers. The term article of manufacture, as used herein, is intendedto encompass a computer program accessible from any computer-readabledevice, carrier, or media.

FIG. 7 depicts a first example method 700 utilizes transmit (Tx)diversity on uplink for potentially more reliable radio access by a userequipment (UE) to the network from Idle mode (e.g., for a MT call, for aMO call, for Registration, etc.).

At block 702, a UE may determine that an access procedure is to beinitiated. In an aspect in which a MO call is initiated, UE 902application processing module 910 may provide a message 928 to accessprocedure module 908 indicating that application data 926 fromapplication 911 is available to be communicated. In such an aspect,access procedure module 908 may determine that an access procedure is tobe initiated based on reception of the message 928. In an aspect inwhich there is a MT call, reception module 904 may receive, using one ormore antennas 906, a page 920 from a network entity 430 indicating thata MT call has been initiated. In such an aspect, access procedure module908 may determine that an access procedure is to be initiated based onreception of the page 920. The UE may be enabled in use one or moreaccess technologies, such as but not limited to, a 1x based accessnetwork, a evolved data optimized (EV-DO) based access network, a codedivision multiple access (CDMA) based network, UMTS based network, along term evolution (LTE) based access network, etc. Where the UE isenabled using a 1x (e.g., EV-DO) based access network, an access probetransmission may indicate initiation of the access procedure. Where theUE is enabled using a CDMA based access network (e.g., WCDMA), a UMTSbased network, a LTE based network, etc., transmission of an accesschannel preamble may indicate initiation of the access procedure. Wherethe UE is enabled to use a LTE based access network and a MT call isindicated from the network, a UTRAN communicates with UE through paging.In such an aspect, paging occurs through setting a Paging Indicator (PI)symbol ON in PICH channel. Further, when the UE wakes up in its DRXcycle, the UE monitors for a PI symbol. Still further, when the UEdetects that the PI symbol is set to ON, the UE reads paging messages ofPCH Tr Ch in SCCPCH physical channel (which occurs Tau _(—) _(PICH) (3slots, or 7680 chips) later. The UE may then initiate the RACH procedureto obtain radio access to send a RRC Connection Request message. Inanother aspect, when there is a MO call or Registration, UE may usesubstantially the same sequence of events as described for a MT call,except for replacing the ‘SCCPCH Complete’ step may be replaced with‘Higher layer indication for physical channel setup’ and everythingprior to this step may be considered redundant.

At block 704, the UE may perform receive (Rx) chain measurements for twoor more antennas associated with the UE. In an aspect, reception module904 may perform receive chain measurements 922 for the two or moreantennas 906. Generally, an antenna that has greater Rx chainmeasurement value may also have less path loss on a downlink. As such,the antenna may also have a greater chance of having lower path loss onan uplink. In an aspect, the receive chain measurements may include, butare not limited to, a RSCP measurement, a RSRP measurement, a RSSImeasurement, an AGC measurement, etc. In an aspect in which the UE hastwo antennas, receive chain measurements may be performed each of theantennas. In an aspect in which the UE has antennas associated withvarious access technologies (e.g., 1x, EV-DO, WCDMA, UMTS, LTE, etc),the UE may either determine which access technology with which toperform measurements and/or may perform measurements based on adetermined a hierarchy among the various access technologies. Forexample, when the UE has multiple receiving circuits available, the UEmay turn on all receiving circuits concurrently, and measure allantennas' performance for comparison. In another example, when the UEhas a single receiving circuit, the UE may connect different antennas tothat single receiving circuit in serial, and measure each antennaperformance sequentially for the comparison.

At block 706, the UE may select an antenna from the two or more antennasbased on the receive chain measurements. In an aspect, reception module904 may provide the receive chain measurements 922 to access proceduremodule 908. Further, access procedure module 908 selection algorithmmodule 909 may make a selection 924 for which antenna to use fortransmission. Further, the antenna selection 924 may be provided totransmission module 912. In an aspect, the UE may select the antennawith the greatest receive chain measurement value. In another aspect,the UE may select the antenna from one or more antennas with receivechain measurement values higher than a threshold level. In an aspect inwhich the UE is enabled to access a LTE based access network, theselection may occur once each access channel cycle. In another aspect,the selection may occur prior to the onset of each preamble in an accesschannel cycle.

At block 708, the UE may perform the access procedure using the selectedantenna. In an aspect, transmission module 912 may perform the accessprocedure using the selected 924 antenna. After successful completion ofthe access procedure, application 911 data 926 may be transmitted, viatransmission module 912, to a network entity 430.

In an optional aspect, at block 710, the UE may determine whether theaccess procedure was successful. The process may end when the UEdetermines the access procedure was successful.

By the contrast, in the optional aspect when the UE determines that theaccess procedure was not successful, at block 712, the UE may select anantenna for use during the at least a portion of the Access procedurebased on one or more subsequent try selection criteria. In an aspect,the newly selected antenna may be based on the previously performed, ornewly preformed receive chain measurements. In another aspect, the newlyselected antenna may be randomly selected. In another aspect, wherethere are two antennas, the previously unselected antenna may beselected. In still another aspect, where there are three or moreantennas, the antenna used in the previously attempt may be removed froma selection pool, and the newly selected antenna may be selected fromthe remaining antennas in the selection pool based on receive chainmeasurements.

FIG. 8 depicts a second example method 800 utilizes Tx diversity onuplink for potentially more reliable radio access by a UE to the networkfrom Idle mode.

At block 802, a UE may determine that an access procedure is to beinitiated. In an aspect in which a MO call is initiated, UE 902application processing module 910 may provide a message 928 to accessprocedure module 908 indicating that application data 926 fromapplication 911 is available to be communicated. In such an aspect,access procedure module 908 may determine that an access procedure is tobe initiated based on reception of the message 928. In an aspect inwhich there is a MT call, reception module 904 may receive, using one ormore antennas 906, a page 920 from a network entity 430 indicating thata MT call has been initiated. In such an aspect, access procedure module908 may determine that an access procedure is to be initiated based onreception of the page 920.

At block 804, the UE may select an antenna from two or more antennasbased on a selection algorithm. In an aspect, access procedure module908 selection algorithm module 909 may prompt 924 the UE 902 to selectan antenna from two or more antennas based on a selection algorithm. Inan aspect, the selection algorithm module 909 may prompt 924 the UE 902to randomly and/or pseudo-randomly select an antenna for use during atleast a portion of the Access procedure. In another aspect, theselection algorithm module 909 may prompt 924 the UE 902 to select anantenna based on a pre-determined antenna hopping pattern (e.g., antenna0, then 1, then 0, then 1, etc.). In another aspect, the selectionalgorithm module 909 may prompt 924 the UE 902 to use an antenna thatwas most recently previously successfully used.

At block 806, the UE may perform the Access procedure. In an aspect,transmission module 912 may perform the access procedure using theselected 924 antenna. After successful completion of the accessprocedure, application 911 data 926 may be transmitted, via transmissionmodule 912, to a network entity 430.

FIG. 9 is a conceptual data flow diagram 900 illustrating the data flowbetween different modules/means/components in an example apparatus 902.The apparatus may be a service layer module associated with a wirelessdevice (e.g., UE 110, UE 202, wireless device 402, etc.). As noted abovewith respect to the flowcharts describe in FIGS. 7 and 8, the apparatus902 may include a reception module 904 associated with two or moreantennas 906, an access procedure module 908 including one or moreselection algorithm modules 909, an application processing module 910supporting one or more applications 911, and a transmission module 912.

The apparatus may include additional modules that perform each of thesteps of the algorithm in the aforementioned call flows and/or flowchart of FIGS. 7 and 8. As such, each step in the aforementioned FIGS. 7and 8 may be performed by a module and the apparatus may include one ormore of those modules. The modules may be one or more hardwarecomponents specifically configured to carry out the statedprocesses/algorithm, implemented by a processor configured to performthe stated processes/algorithm, stored within a computer-readable mediumfor implementation by a processor, or some combination thereof.

FIG. 10 is a diagram 1000 illustrating an example of a hardwareimplementation for an apparatus 902′ employing a processing system 1014.The processing system 1014 may be implemented with a bus architecture,represented generally by the bus 1024. The bus 1024 may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system 1014 and the overall designconstraints. The bus 1024 links together various circuits including oneor more processors and/or hardware modules, represented by the processor1004, the modules 904, 908, 909, 910, 812, and the computer-readablemedium 1006. The bus 1024 may also link various other circuits such astiming sources, peripherals, voltage regulators, and power managementcircuits, which are well known in the art, and therefore, will not bedescribed any further.

The processing system 1014 may be coupled to a transceiver 1010. Thetransceiver 1010 is coupled to two or more antennas 1020. Thetransceiver 1010 provides a means for communicating with various otherapparatus over a transmission medium. The processing system 1014includes a processor 1004 coupled to a computer-readable medium 1006.The processor 1004 is responsible for general processing, including theexecution of software stored on the computer-readable medium 1006. Thesoftware, when executed by the processor 904, causes the processingsystem 1014 to perform the various functions described supra for anyparticular apparatus. The computer-readable medium 1006 may also be usedfor storing data that is manipulated by the processor 1004 whenexecuting software. The processing system further includes at least oneof the modules 904, 908, 909, 910, and 912. The modules may be softwaremodules running in the processor 1004, resident/stored in thecomputer-readable medium 1006, one or more hardware modules coupled tothe processor 1004, or some combination thereof In an aspect, theprocessing system 1014 may be a component of the UE 350 and may includethe memory 360 and/or at least one of the TX processor 368, the RXprocessor 356, and the controller/processor 359.

In a configuration, the apparatus 902/902′ for wireless communicationincludes means for obtaining, by a UE, receive chain measurements fortwo or more antennas associated with the UE when an access procedure isinitiated, means for selecting an antenna, of the two or more antennas,for transmission based on receive chain measurements for use during atleast a portion of the access procedure, and means for performing theaccess procedure using the selected antenna. In an aspect, apparatus902/902′ may include means for determining that the performed accessprocedure was unsuccessful. In such an aspect, apparatus 902/902′ meansfor selecting may be further configured to select a new antenna from thetwo or more antennas based on one or more subsequent try selectioncriteria. Further, in such an aspect, apparatus 902/902′ means forperforming may be further configured to perform the access procedureusing the selected new antenna. In such an aspect, apparatus 902/902′may include means for determining that the access procedure is to beinitiated.

In another configuration, the apparatus 902/902′ for wirelesscommunication includes means for determining that an Access procedure isto be initiated, means for selecting an antenna, from the two or moreantennas, for transmission based on a selection algorithm, and means forperforming the Access procedure based using the selected antenna. In anaspect, the selection algorithm may include randomly selecting theantenna from the two or more antennas. In an aspect, the selectionalgorithm may include selecting the antenna based on a hopping patternamong the two or more antennas. In an aspect, the selection algorithmmay include selecting the antenna based on an antenna that was mostrecently successfully used for the Access procedure.

As described supra, the processing system 1014 may include the TXProcessor 368, the RX Processor 356, and the controller/processor 359.As such, in one configuration, the aforementioned means may be the TXProcessor 368, the RX Processor 356, and the controller/processor 359configured to perform the functions recited by the aforementioned means.

It is understood that the specific order or hierarchy of steps in theprocesses disclosed is an illustration of exemplary approaches. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the processes may be rearranged. Further, somesteps may be combined or omitted. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. All structural andfunctional equivalents to the elements of the various aspects describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are expressly incorporated herein byreference and are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed as a means plus functionunless the element is expressly recited using the phrase “means for.”

What is claimed is:
 1. A method of communications for a user equipment(UE), comprising: obtaining, by a UE, receive chain measurements for twoor more antennas associated with the UE when an access procedure isinitiated; selecting an antenna, of the two or more antennas, fortransmission based on receive chain measurements for use during at leasta portion of the access procedure; and performing the access procedureusing the selected antenna.
 2. The method of claim 1, wherein thereceive chain measurements comprise at least one of: a receive signalcode power (RSCP) measurement; a Reference Signal Received Power (RSRP)measurement; a Received Signal Strength Indication (RSSI) measurement;or an automatic gain control (AGC) measurement.
 3. The method of claim1, wherein the UE is configured to operate in at least one of a longterm evolution (LTE) based access network, a Universal MobileTelecommunications System (UMTS) based network, or a code divisionmultiple access (CDMA) based network, and wherein the access procedureis a access channel (ACH) procedure.
 4. The method of claim 3, whereinthe receive chain measurements are obtained and the antenna selection isperformed once for a ACH cycle.
 5. The method of claim 3, wherein thereceive chain measurements are obtained and the antenna selection isperformed prior to an onset of each preamble in a ACH cycle.
 6. Themethod of claim 1, further comprising: determining that the performedaccess procedure was unsuccessful; selecting a new antenna from the twoor more antennas based on one or more subsequent try selection criteria;and performing the access procedure using the selected new antenna. 7.The method of claim 6, wherein the one or more subsequent try selectioncriteria comprise at least one of: a greatest receive chain measurementvalue based on newly performed receive chain measurements; a nextgreatest receive chain measurement value based on previously performedreceive chain measurements; an antenna different than the previouslyselected antenna, where the two or more antennas comprises two antennas;an antenna from a pool of antennas that does not include the previouslyselected antenna, where the two or more antennas comprises more than twoantennas; or a random antenna selection.
 8. The method of claim 1,further comprising: determining that the access procedure is to beinitiated.
 9. The method of claim 8, wherein the determination that theaccess procedure is to be initiated is based on reception of a pagingindicator.
 10. The method of claim 8, wherein the determination that theaccess procedure is to be initiated is based on internal reception of amessage to prompt the UE to engage in a mobile originated (MO) call. 11.The method of claim 1, wherein the UE is configured to operate is a 1xbased access network, and wherein the access procedure is an accessprobe procedure.
 12. A method of method of communications for a userequipment (UE), comprising: determining that an Access procedure is tobe initiated; selecting an antenna, from the two or more antennas, fortransmission based on a selection algorithm; and performing the Accessprocedure based using the selected antenna.
 13. The method of claim 12,wherein the selection algorithm comprises randomly selecting the antennafrom the two or more antennas.
 14. The method of claim 12, wherein theselection algorithm comprises selecting the antenna based on a hoppingpattern among the two or more antennas.
 15. The method of claim 12,wherein the selection algorithm comprises selecting the antenna based onan antenna that was most recently successfully used for the Accessprocedure.
 16. An apparatus for communications by a user equipment (UE),comprising: means for obtaining, by a UE, receive chain measurements fortwo or more antennas associated with the UE when an access procedure isinitiated; means for selecting an antenna, of the two or more antennas,for transmission based on receive chain measurements for use during atleast a portion of the access procedure; and means for performing theaccess procedure using the selected antenna.
 17. An apparatus forcommunications by a user equipment (UE), comprising: means fordetermining that an Access procedure is to be initiated; means forselecting an antenna, from the two or more antennas, for transmissionbased on a selection algorithm; and means for performing the Accessprocedure based using the selected antenna.
 18. A computer programproduct, comprising: a non-transitory computer-readable mediumcomprising code for: obtaining, by a UE, receive chain measurements fortwo or more antennas associated with the UE when an access procedure isinitiated; selecting an antenna, of the two or more antennas, fortransmission based on receive chain measurements for use during at leasta portion of the access procedure; and performing the access procedureusing the selected antenna.
 19. A computer program product, comprising:a non-transitory computer-readable medium comprising code for:determining, by a user equipment (UE), that an Access procedure is to beinitiated; selecting an antenna, from the two or more antennas, fortransmission based on a selection algorithm; and performing the Accessprocedure based using the selected antenna.
 20. An apparatus forcommunications, comprising: a processing system configured to: obtain,by a UE, receive chain measurements for two or more antennas associatedwith the UE when an access procedure is initiated; select an antenna, ofthe two or more antennas, for transmission based on receive chainmeasurements for use during at least a portion of the access procedure;and perform the access procedure using the selected antenna.
 21. Theapparatus of claim 20, wherein the receive chain measurements compriseat least one of: a receive signal code power (RSCP) measurement; aReference Signal Received Power (RSRP) measurement; a Received SignalStrength Indication (RSSI) measurement; or an automatic gain control(AGC) measurement.
 22. The apparatus of claim 20, wherein the UE isconfigured to operate in at least one of a long term evolution (LTE)based access network, a Universal Mobile Telecommunications System(UMTS) based network, or a code division multiple access (CDMA) basednetwork, and wherein the access procedure is a access channel (ACH)procedure.
 23. The apparatus of claim 22, wherein the receive chainmeasurements are obtained and the antenna selection is performed oncefor a ACH cycle.
 24. The apparatus of claim 22, wherein the receivechain measurements are obtained and the antenna selection is performedprior to an onset of each preamble in a ACH cycle.
 25. The apparatus ofclaim 20, wherein the processing system is further configure to:determine that the performed access procedure was unsuccessful; select anew antenna from the two or more antennas based on one or moresubsequent try selection criteria; and perform the access procedureusing the selected new antenna.
 26. The apparatus of claim 25, whereinthe one or more subsequent try selection criteria comprise at least oneof: a greatest receive chain measurement value based on newly performedreceive chain measurements; a next greatest receive chain measurementvalue based on previously performed receive chain measurements; anantenna different than the previously selected antenna, where the two ormore antennas comprises two antennas; an antenna from a pool of antennasthat does not include the previously selected antenna, where the two ormore antennas comprises more than two antennas; or a random antennaselection.
 27. The apparatus of claim 20, wherein the processing systemis further configure to: determine that the access procedure is to beinitiated.
 28. The apparatus of claim 27, wherein the determination thatthe access procedure is to be initiated is based on reception of apaging indicator.
 29. The apparatus of claim 27, wherein thedetermination that the access procedure is to be initiated is based oninternal reception of a message to prompt the UE to engage in a mobileoriginated (MO) call.
 30. The apparatus of claim 20, wherein the UE isconfigured to operate is a 1X based access network, and wherein theaccess procedure is an access probe procedure.
 31. An apparatus forcommunications, comprising: a processing system configured to:determine, by a user equipment (UE), that an Access procedure is to beinitiated; select an antenna, from the two or more antennas, fortransmission based on a selection algorithm; and perform the Accessprocedure based using the selected antenna.
 32. The apparatus of claim31, wherein the processing system is further configure to randomlyselect the antenna from the two or more antennas.
 33. The apparatus ofclaim 31, wherein the processing system is further configure to selectthe antenna based on a hopping pattern among the two or more antennas.34. The apparatus of claim 31, wherein the processing system is furtherconfigure to select the antenna based on an antenna that was mostrecently successfully used for the Access procedure.